Monthly skin self-exams are an important supplement to annual professional skin cancer screenings. They help you notice changes early — and early detection is the single most important factor in skin cancer survival. This guide covers the ABCDE criteria for melanoma, warning signs for basal cell and squamous cell carcinoma, and how to perform an effective self-exam at home.
The ABCDE Rule for Melanoma
- A — Asymmetry
- One half of the mole does not match the other. Benign moles are typically symmetrical.
- B — Border
- Irregular, ragged, notched, or blurred edges. Benign moles have smooth, well-defined borders.
- C — Color
- Variation within a single lesion — shades of brown, black, red, white, or blue within the same spot.
- D — Diameter
- Larger than 6mm (the size of a pencil eraser). Most melanomas are larger than this at diagnosis.
- E — Evolving
- Any change in size, shape, color, or any new symptom — itching, bleeding, crusting. The most important criterion: a changing mole deserves evaluation regardless of other ABCDE features.
Warning Signs for BCC and SCC
Basal Cell Carcinoma (BCC) — Most Common Skin Cancer
- Pearly or waxy bump, often with visible blood vessels
- Flat, flesh-colored or brown scar-like lesion
- Bleeding or scabbing sore that heals and returns repeatedly
- Pinkish patch of irritated skin that doesn’t resolve
Squamous Cell Carcinoma (SCC)
- Firm, red nodule or rough, scaly patch
- Flat lesion with a scaly, crusted surface
- New sore or raised area on an old scar
- Wart-like growth that won’t go away
How to Perform a Skin Self-Exam
- Choose good lighting. A bright room after showering. Use a full-length and handheld mirror.
- Examine your face. Check nose, lips, ears, and scalp. Part your hair to check the scalp with a comb.
- Check your neck and chest. Include the collarbone area and décolletage.
- Inspect your arms. Between fingers, under fingernails, elbows, and underarms.
- Examine your torso. Use a full-length mirror for the back, lower back, and buttocks.
- Check your legs. Front and back of thighs, shins, between toes, under toenails, and soles of feet.
- Document anything new. Photograph concerning spots with your phone and note the date.
Frequently Asked Questions
How often should I check my skin at home?
Monthly self-exams are the standard recommendation. Pick a consistent time and systematically examine every area of your skin.
What if I find a suspicious spot?
Call your dermatologist promptly. Do not wait to see if it goes away. Early detection dramatically improves outcomes — if the spot is benign, you’ll have peace of mind; if not, early treatment is far more effective.
Does skin cancer always look like a mole?
No. Basal cell carcinoma often looks like a pink, pearly bump or a persistent pimple that won’t heal. Squamous cell carcinoma often appears as a rough, scaly patch or wart-like growth. Only melanoma consistently resembles a mole.
Can skin cancer appear in areas that never see the sun?
Yes. Melanoma can occur anywhere — including the palms, soles, inside the mouth, and under fingernails. Merkel cell carcinoma and other rare skin tumors are not exclusively UV-driven.
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Belaray Dermatology education articles are written by our clinical team and medically reviewed by our physicians. This article draws on guidance from the following authoritative sources:
- American Academy of Dermatology — Skin cancer overview, detection, and self-exams.
- American Cancer Society — Skin cancer facts and statistics.
- Skin Cancer Foundation — Prevention, early detection, and treatment.